Centrifugal switch.



A. H. BAKKEN.

CENTRIFUGAL SWITCH.

APPLICATION FILED JAN.24-. 1914.

1,224, 126. Patented May 1, 1917.

2 SH EETSSHEET I.

-INVENTOR ATTORNEY A. H. BAKKEN.

CENTRIFUGAL SWITCH.

APPLICATION FILED IAN. 24.1914.

2 SHEETSSHEET 2.

Fig. 3.

= IKINVENjIgR 2 I BY Z ATTORNEY Patented May 1, 1917.

p 35 front elevation, of an end .UN'ITED STATES PATENT orrioni ANDREW H. BAKKEN, or wILkINsBUBe, PENNSYLVANIA; nssrenon '10 wnsrine-' HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

CENTRIFUGAL SWITCH.

Specification of Letters Patent.

Patented May 1, 1917.

Application filed January 24, 1914. Serial No. 814,054.

To all whom it may concern:

Be it known that I, ANDREW H. BAKKEN, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Centrifugal Switches, of which the following is a specification.

My invention relates to centrifugal switches such as are employed in connection with electrical devices in which circuit connections are made and interrupted at predetermined speeds, and it has for its object to provide a switching device of the above indicated character which shall be simple and durable in construction and positive and certain in its action under all conditions.

It is desirable, in practice, to provide single phase motors for various applications with auxiliary windings of high resistance for starting. It is desirable also, to provide a suitable device for controlling the circuit connections of this winding in order to avoid unnecessary power losses that may be caused by leaving the auxiliary winding in circuit.

My invention provides a operated switch by means of centrifugally which the cir- V cuit of the auxiliary winding is automati-. so cally broken when a predetermined speed is reached and is closed again upon the speed falling off to a predetermined minimum or when the motor stops.

In the drawings, Figure 1 is a view, in

bracket of an induction motor with the stationary member of the switch applied thereto; Fig. 2 is a view, partially in section and partially in side elevation, of an induction motor with both the stationary and rotatable members of the switch applied thereto; Fig. 3 is a view, in front elevation, of the rotating member of the switch; Fig. 4 is a plan view of one of the centrifugally actuated memhers shown in Fig. 3. Fig. 5 is a view in section on the line V-V of Fig. 4. Fig. 6

is a diagrammatic view of the motor windings and the switch.

Referring particularly to Figs. 2 and 3,

an induction motor 1 has a rotor 2 upon the front face of which is mounted the rotatable member of the centrifugal switch. The

rotatable member comprlses an annular plate member 3 that is attached to the rotor 2 by screws 4, the plate 3 being suitably spaced from the rotor 2 by spacing sleeves 5. Curved members 6 have a pivotal support upon pins 7 that are attached to the plate member 3. Any desired number of members may be employed, four being shown in the preferred form of my invention.

As best shown in Figs. 4 and 5, each member 6 consists of a reduced portion or arm 8 that is arched or'off-set at an intermediate portion 9 so that the respective portions lie in different planes. The portion 8 is provlded, at one end, with a hole 10 to provide a bearing for the pin 7. The member 6 consists also of a curved body portion 11, the edges of which are bent at right angles to form flanges 12 and 13 that have substantially the form of arcs of circles. The body portion 11 is provided, at an intermediate portion, with an opening 14 to permit relative movement of the several members 6 when they are in operation, as will be later described.

Referring now to Fig. 3, the members 6 are mounted upon the plate member 3, with the reduced portion 8 of each member overlapping the body portion 11 of the adjacent member, the arched or off-set portion 9 permitting the members to lie in the same plane and to be interlocked by arranging the pins 7 within the opening 14. The flanges 12 are provided with indented portions 15 which coact with the arched portions 9 of the adj acent members to insure that an outward movement of one of the members about its pivot will cause a corresponding movement of the member with which it is connected. The flanges 13 coact with the arched portions 9 to produce a simultaneous inward movement of the several members. The members 6 are yieldingly retained in their inward positions by a garter spring 16 which embraces the several flanges 13. The portions 11 are so curved that approximate circles are presented by their combined outer peripheries and combined inner peripheries in any position assumed by the members 6 as they are actuated by centrifugal force. The outward and inward movements of the several members 6 are limited by the engagementof the walls of the opening 14 with the adjacent end portions 8 surrounding the his 7. The stationary member of mounted upon a stationary motor, as, for example, upon the inner the switch is part of the face of the end casing 17 (Fig. 1). A base plate;

18, which is attached by screws 19 to the end are pivotally supported by pins 22.

A spring 23, which is connected at its ends to cars 24.- on the respective arms 21, yieldingly retains the arms in the position illustrated in Fig. 1, or in their outward position, according as the arms are actuated inwardly or outwardly. When the arms 21 are in such position that the several cars 24 and pins 22 are in alinement, the arms 21 are in unstable equilibrium, and the spring 23 tends to rock the arms about their pivots in opposite directions when the arms are on opposite sides of the above described position.

Each of the arms 21 comprises a main portion 25, an end portion 26, which carries a contact member 27, and an insulating member 28 which connects the end portion 26 to,and insulates it from, the main portion 25. Each arm 21 is provided, upon its inner and outer peripheries, respectively, with curved projections 29 and 30 to coact withthe members 6, according as they are actuated inwardly by the spring 16 or out wardly by centrifugal force.

Reference may now be had to Fig. 6-in which a main motor winding 31 and an auxiliary or starting winding 32 are diagrammatically illustrated. The main windmg 31 is connected to conductors 33 and 34 which may be co'nnected to any suitable source of current. The auxiliary winding 32, which is connected in parallel with the main winding 31, is connected in circuit with the contact members 27.

It may be assumed that the several parts of the rotatable member of the switch are in the respective positions illustrated in Fig. 3 and that the several parts of the stationary member occupy the respective positions shown in Fig. 1, with the flanges approximately equidistant from the respective coacting surfaces of the members 6. When the circuit of the motor is closed through an suitable connections and the motor spee increases, the members 6 are actuated by centrifugal force to fly outwardly about their pivots 7 and against the tension of the spring 16; When the motor reaches a predetermined speed, the members 6-have assumed a position corresponding to that indicated by dotted lines in Fig. 3, only one of the members being so shown, whereupon the several flanges 12 engage the projections 30 of the switch arms 21. The arms 21 are thus actuated outwardly against the tension of the spring 23 until they pass the mid-position above described when the spring actuates them to their respective outer positions in engagement with stops 35 that are integral with the base plate 3.

tracts the members 6 and their inner peripheries engage the projections 29, and the arms 21 are actuated inwardly to effect the en-- gagement of the contact members and thereby complete the circuit of the auxiliary wmdin ready for starting or acceleration.

The advantages of a switch constructed in accordance with my invention are that it is positive and automatic in action at any desired speed. The speeds at which the switch operates may be determined by properly proportioning the weights of the members 6 or by varying the tension of the spring 16. By reason of the approximately cylindrical surface presented by the flanges 12 and 13 of the members 6, in both the expanded and contracted positions, the actuation of the switch arms 21 is accomplished easily and gradually, and the striking of a blow by rotating parts is avoided. By employing two movable arms instead of one, as in devices of this character as heretofore constructed, a very quick action is obtained in both opening and closing the switch.

I claim as m invention:

1. The com ination with a rotatable shaft, of a composite ring carried thereby, said ring being adapted to increase in diameter with an increase in the speed ofrotation of the said shaft and to decrease in diameter with a decrease in its speed, a pair of pivotally mounted switch members, means for biasing the said switch members toward either the open or the closed position, and operating lugs carried by each of said switch members and adapted to be engaged by the inner and the outer surfaces of the said ring to actuate the said switch members in opposite directions.

2. The combination with a rotatable shaft, of a composite ring carried thereby, said ring being adapted to increase in diameter with an increase in the speed of rotation of the said shaft and to decrease in diameter with a decrease in its speed, a pair of pivotally mounted switch members, and operating lugs carried by each of said switch members and adapted to be engaged by the inner and the outer surfaces of the said ring to simultaneously actuate the said switch members in opposite directions at I predetermined speeds.

ried thereby and comprising a base plate at tached thereto, a plurality of pivotally mounted members each of which is provided with a curved flanged portion, and a continuous resilient member engaging the flanged portions of all of said members and tending to draw the said pivotally mounted members inwardly.

4. The combination with a rotatable element, of a centrifugal operating device carried thereby and comprising a base plate attached thereto, a plurality of pivotally. mounted members severally terminating in a curved portion provided with substan-,

tially concentric flanges, and a circular spring engaging the said flanges and tending to draw the said pivotally mounted members inwardly.

'5. The combination with a rotatable element, of a centrifugal operating device carried thereby and comprising a base plate attached thereto, a plurality of members each of which is pivoted at one erd to the said base plate and terminates in a curved portion provided with an opening through which the pivotal support of the adjacent member extends.

6. The combination with a rotatable element, of a centrifugal operating device carried therebyand comprising a base plate attached thereto, a plurality of members each of which is pivoted at one end to the said base plate and terminates'in a curved portion provided with an opening through which the pivotal support of the adjacent member extends, the walls of the said openings limiting the movements of the said pivotally mounted members.

In testimony whereof, I have hereunto subscribed my name this 17th day of J an., 1914.

ANDREW H. BAKKEN.

Witnesses:

DAVID SAMUEL, B. B. HINES. 

